Cystic fibrosis (CF) is a common inherited disease which causes significant shortening of life expectancy and severe morbidity among the affected children and young adults. Since CF was first described nearly 40 years ago, there has been considerable research on the basic molecular defect of the disease and the resultant pathogenesis. Although significant studies have been made in the latter area, the basis underlying defect remains unknown. In recent years, however, a number of researchers have reported "biological factors," which may be associated with the basic defect, which may distinguish CF homozygotes, heterozygotes and unaffected individuals. These findings have been applied to development of procedures for heterozygote detection and prenatal diagnosis. To date, a number of different techniques have been developed and tested on relatively small sample populations. These tests have aroused interest and contraversy within the professional and lay communities. Further there are many issues and unanswered questions. The proposed conference will address the issues, controversies and implications related to the basic biological defect in CF and the potential development of heterozygote screening/prenatal diagnosis of CF by examining: the status of research to date; the relationship of findings (and developed procedures) to the pathophysiology of CF; future research needs and directions. The conference will include the input of experts in the area, including those with divergent views and researchers not directly involved in research on CF but renowned for their efforts in allied fields. The conference results will be documented in reports for professional and lay audiences.